The journal of pain : official journal of the American Pain Society
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Randomized Controlled Trial
Effects of a selective cyclooxygenase-2 inhibitor on postoperative inflammatory reaction and pain after total knee replacement.
The goal of this study was to evaluate the systemic and peripheral effects of preoperative administration of cyclooxygenase-2 inhibitor on pain and inflammation occurring with total knee replacement (TKR). Patients undergoing elective TKR were prospectively and randomly given oral rofecoxib (25 mg) or placebo (control group) 1 hour before surgery. All patients received an epidural combined with isoflurane anesthesia during the operation and patient-controlled epidural analgesia postoperatively. The outcome measures included pain scores during rest and movement of knee joints and cumulative morphine consumption. Femoral blood and knee joint drainage fluids were examined for leucocyte numbers and concentrations of cytokines (including IL-6, IL-8, IL-10, and TNF-alpha). Periarticular circumferential increments at 48 hours served as an indication of inflammatory edema. Pain scores during rest and knee joint movement on postoperative days 1 and 2 were better in those given rofecoxib than in control subjects, and cumulative morphine consumption for the first 24 hours was significantly reduced. Both groups had higher concentrations of IL-6 and IL-8 in knee drainage fluid compared with serum levels. Rofecoxib significantly decreased regional IL-6 and TNF-alpha level after surgery. Moreover, the incidence of febris and degree of local edema were lower in the rofecoxib group (P < .05), and peripheral IL-6 level significantly correlated with pain score at 48 hours. Preoperative administration of rofecoxib increases patient satisfaction with analgesia, reduces opioid requirement, and decreases both systemic and local anti-inflammation after TKR. ⋯ This randomized, double-blinded trial shows that preoperative administration of rofecoxib can greatly ameliorate the pain occurring with total knee joint replacement surgery and its accompanying reduction of general and local inflammatory reactions.
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Accurate evaluation of pain plays a critical role in identifying new interventions for the treatment and prevention of herpes zoster and postherpetic neuralgia (PHN). Different types of pain and other sensory symptoms are found in patients with herpes zoster, and these vary greatly with respect to their presence, location, duration, intensity, and quality. The results of recent studies of herpes zoster and PHN and the development of new methods for assessing neuropathic pain provide a foundation for diagnosing and assessing the pain associated with herpes zoster. We review the results of recent research to identify the essential components that must be considered in developing an evidence-based description of pain associated with herpes zoster and PHN. ⋯ Comprehensive assessments of pain are necessary for clinical research on the epidemiology, natural history, pathophysiologic mechanisms, treatment, and prevention of pain in herpes zoster and PHN.
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The method of pain-evoked potentials has gained considerable acceptance over the last 3 decades regarding its objectivity, repeatability, and quantifiability. The present study explored whether the relationship between pain-evoked potentials and pain psychophysics obtained by contact heat stimuli is similar to those observed for the conventionally used laser stimulation. Evoked potentials (EPs) were recorded in response to contact heat stimuli at different body sites in 24 healthy volunteers. Stimuli at various temperatures were applied to the forearm (43 degrees C, 46 degrees C, 49 degrees C, and 52 degrees C) and leg (46 degrees C and 49 degrees C). The amplitudes of both components (N2 and P2) were strongly associated with the intensity of the applied stimuli and with subjective pain perception. Yet, regression analysis revealed pain perception and not stimulus intensity as the major contributing factor. A significant correlation was found between the forearm and the leg for both psychophysics and EPs amplitude. ⋯ Contact heat can generate readily distinguishable evoked potentials on the scalp, consistent between upper and lower limbs. Although these potentials bear positive correlation with both stimulus intensity and pain magnitude, the latter is the main contributor to the evoked brain response.
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Review
A review of objective pain measures for use with critical care adult patients unable to self-report.
Critically ill patients experience significant levels of pain and discomfort from multiple intrinsic and extrinsic sources while in the intensive care unit (ICU). The use of objective pain measures in nonverbal patients is an essential alternative approach for pain assessment when self-reports are unavailable. This paper provides a critical review of the psychometric properties of 6 objective pain measures that were developed to assess pain in nonverbal adult patients in the ICU. The strengths and weaknesses of these objective measures are evaluated, as well as their applicability for use with this patient population. Although 2 of the 6 objective pain measures showed good evidence of validity and reliability, none has undergone vigorous validation or has been accepted as a standardized measure. Findings from the available studies of objective pain measures provide useful information to direct future research to develop and validate clinically useful pain measures for use with critically ill patients unable to self-report. ⋯ This review provides clinicians with a summary of the psychometric properties of 6 objective pain measures and discusses their applicability for use to assess pain in critically ill adult patients unable to self-report.
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Comparative Study
Neuromodulation of thoracic intraspinal visceroreceptive transmission by electrical stimulation of spinal dorsal column and somatic afferents in rats.
Clinical studies have shown that neuromodulation therapies, such as spinal cord stimulation (SCS) and transcutaneous electrical nerve stimulation (TENS), reduce symptoms of chronic neuropathic and visceral pain. The neural mechanisms underlying SCS and TENS therapy are poorly understood. The present study was designed to compare the effects of SCS and TENS on spinal neuronal responses to noxious stimuli applied to the heart and esophagus. Direct stimulation of an intercostal nerve (ICNS) was used to simulate the effects of TENS. Extracellular potentials of left thoracic (T3) spinal neurons were recorded in pentobarbital anesthetized, paralyzed, and ventilated male rats. SCS (50 Hz, 0.2 ms, 3-5 minutes) at a clinical relevant intensity (90% of motor threshold) was applied on the C1-C2 or C8-T1 ipsilateral spinal segments. Intercostal nerve stimulation (ICNS) at T3 spinal level was performed using the same parameters as SCS. Intrapericardial injection of bradykinin (IB, 10 microg/mL, 0.2 mL, 1 minute) was used as the noxious cardiac stimulus. Noxious thoracic esophageal distension (ED, 0.4 mL, 20 seconds) was produced by water inflation of a latex balloon. C1-C2 SCS suppressed excitatory responses of 16/22 T3 spinal neurons to IB and 25/30 neurons to ED. C8-T1 SCS suppressed excitatory responses of 10/15 spinal neurons to IB and 17/23 neurons to ED. ICNS suppressed excitatory responses of 9/12 spinal neurons to IB and 17/22 neurons to ED. These data showed that SCS and ICNS modulated excitatory responses of T3 spinal neurons to noxious stimulation of the heart and esophagus. ⋯ Neuromodulation of noxious cardiac and esophageal inputs onto thoracic spinal neurons by spinal cord and intercostal nerves stimulation observed in the present study may help account for therapeutic effects on thoracic visceral pain by activating the spinal dorsal column or somatic afferents.